1. Field of the Invention
The present invention relates to a resin composition and a thermo/photosensitive composition that can be used as compositions that can be cured by light or heat and used in image recording materials such as three dimensional optical shaping and holography, planographic printing plate materials, color proofs, photo-resists, and color filters, inks, paints, and adhesives. In particular, the invention relates to a resin composition and a thermo/photosensitive composition that can be suitably used as recording materials of negative type planographic printing plate precursors capable of so-called direct plate-making which can be directly made a plate with various lasers based on digital signals of a computer and the like.
2. Description of the Related Art
In recent years, development of lasers is remarkable; in particular, solid lasers, semiconductor lasers, and gas lasers that emit UV light, visible light, and infrared light in the wavelength range of from 300 to 1200 nm, can be easily obtained as ones that are high in power and small in size. The lasers are very useful as a recording light source when the direct palate making based on digital data of such as a computer is performed in planographic printing. There are various studies on the image recording materials that respond to various laser lights; positive image recording materials that respond to infrared lasers of a photosensitive wavelength of 760 nm or more (such as those described in U.S. Pat. No. 4,708,925), and acid-catalyst crosslinking negative image recording materials (such as those described in Japanese Patent Application Laid-Open (JP-A) No. 8-276558) are known. Furthermore, radical polymerizing negative image recording materials that respond to UV light or visible light in the range of from 300 to 700 nm are also known (such as those described in U.S. Pat. No. 2,850,445 and Japanese Patent Publication (JP-B) No. 44-20189).
Normally, such a negative image recording material contains a compound that generates radicals when exposed to light or heat and a polymerizable compound, and a recording method is utilized in which a polymerization reaction is caused by the radicals generated when exposed to light or heat as an initiator, thereby an image recording layer in an exposed portion is cured, and thereby an image area is formed. Such negative image recording materials are low in the image forming property in comparison with positive image recording materials in which a recording layer is made soluble by energy of laser irradiation. Accordingly, with an intention of accelerating a curing due to polymerization and thereby forming a image area with strength, heat treatment is generally applied before development.
As printing plates that have such an image recording layer formed by the polymerization caused by light or heat, techniques (such as those described in JP-A Nos. 8-108621 and 9-34110) that use a photo-polymerizable or heat polymerizable composition as a recording layer are known. These image-recording layers are excellent in the high sensitivity image forming property. However, when a hydrophilicity-imparted substrate that is used as a support, there is a problem in that since adhesion at an interface between the image recording layer and the support is low, the press life is short.
Furthermore, in order to improve sensitivity, use of infrared lasers of higher output is under study; however, there is a problem in that an optical system is contaminated by generation of ablation of a recording layer during laser scanning. Other than this, chemical amplification-type sensitive materials (such as those described in JP-A No. 11-65105) and sensitive materials that utilize polymerization of ethylenic unsaturated compounds (such as those described in JP-A No. 2000-89455) are under study. However, since these sensitive materials contain components excellent in the reactivity to light and heat, there is concern in that handling under white light or variation of an environmental temperature tends to cause an undesirable reaction, that is, their shelf-stability is poor.